The document provides instructions and content for a biology exam consisting of two papers to be taken on March 15, 2012. Paper I contains 20 multiple choice questions testing concepts in biology. Paper II contains 8 questions in various formats assessing topics such as DNA structure and replication, protein synthesis, and cell division. Students are instructed to answer all questions in the spaces provided using pen only and clear handwriting. The document also provides the scoring rubrics for each paper based on the total number of points earned.

1. DecimoNacional Name Student:
Biology
Exam I& II
10 Nal
1 hour30 minutes
Thursday 15 March 2012
INSTRUCTIONS TO CANDIDATES
Do not open this examination paper until instructed to do so.Answer all the questions.
For each question, choose the answer you consider to be the best and indicate your choice
Answer all in the spaces provided. Use pen only. Use clear handwriting
Paper I
Puntos Nota
19-20 7
17-18 6
15-16 5
12-14 4
8-11 3
3-7 2
1-2 1
Paper II
Puntos Nota
35-40 7
30-34 6
26-29 5
20-25 4
11-19 3
6-10 2
1-5 1
Paper I
1.Which structure is found in all prokaryotic cells?
A. Flagella
EJE 1

2. B. Ribosomes
C. Mitochondria
D. Vacuoles
2. During endocytosis, what change will most likely occur in the plasma membrane of a cell?
A. It will form two phospholipid monolayers.
B. It will become electrically charged.
C. It will partially dissolve.
D. It will form vesicles.
3. Which of the following could be a function of a membrane protein?
A. Energy storage
B. Enzymatic activity
C. Oxygen uptake
D. Thermal insulation
4. In which compounds would a double bond link carbon to oxygen (C=O)?
I. Amino acid
II. Fattyacid
III. Glycerol
A. I and II only
B. II and III only
C. I and III only
D. I, II and III
5. Why is the genetic code described as degenerate?
A. Some codons can cause translation to stop.
B. More than one codon can represent one amino acid.
C. The genetic code is the same in all organisms.
D. Codons can change through mutation.
6. During the process of replication, which bond(s) in the diagram of DNA below is/are broken?
A. 3
B. 4, 5
C. 1, 2, 6, 7
D. 1, 7, 4, 5
7. What is the maximum number of fatty acids that can be condensed with glycerol?
A. One
B. Two
C. Three
D. Four
8. What is the correct order of increasing size for the following biological structures?
I. The width of a virus
II. The width of a bacterium
EJE 2

3. III. The thickness of a cell surface membrane
IV. The diameter of a eukaryotic cell
A. I →III →II →IV
B. I →III →IV →II
C. III →I →II →IV
D. III →II →I →IV
9. The diagram shows part of a molecule produced by replication of DNA. What is the significance of the shaded and the
unshaded regions?
A. The shaded parts are DNA and the unshaded parts are mRNA.
B. The shaded parts contain adenine and thymine and the unshaded parts contain guanine
and cytosine.
C. The shaded part is a codon and unshaded part is an anticodon.
D. One of the parts has been newly synthesised and the other was part of a pre-existing
DNA molecule.
10. If mRNA has a codon CAU, what is the corresponding anticodon on the tRNA molecule?
A. CAT
B. GUA
C. CAU
D. GTA
11. What are pyrimidines in DNA?
A. Types of nucleotides
B. Types of base pairs
C. Types of sugars
D. Types of bases
12. Which enzyme removes the RNA primer during replication?
A. RNA primase
B. DNA polymerase I
C. DNA ligase
D. Helicase
13. Which of the following structures are present in both plant and animal cells?
I. Cell wall
II. Chloroplast
III. Mitochondrion
A. I only
B. I and II only
C. I and III only
D. III only
14. Which of the following is a feature of exocytosis but not endocytosis?
A. Shape changes of a membrane
B. Vesicle formation
EJE 3

4. C. Use of ATP
D. Secretion
15. What is replicated by a semi-conservative process?
A. Messenger RNA (mRNA) only
B. Messenger RNA (mRNA) and transfer RNA (tRNA) only
C. Messenger RNA (mRNA), transfer RNA (tRNA) and DNA only
D. DNA only
16. If 15 % of a sample of DNA is thymine, what percentage of the DNA is guanine?
A. 15 %
B. 30 %
C. 35 %
D. It cannot be determined from the information given.
17. On which molecule is a codon found?
A. Polypeptide
B. mRNA
C. tRNA
D. rRNA
18. Which of these molecules is a disaccharide?
A. Galactose
B. Sucrose
C. Cellulose
D. Ribose
19. What is a codon?
A. A sequence of nucleotides on rRNA that corresponds to an amino acid
B. A sequence of nucleotides on mRNA that corresponds to an amino acid
C. A sequence of nucleotides on tRNA that corresponds to an amino acid
D. A sequence of nucleotides on DNA that corresponds to an amino acid
20. Which molecule is shown below?
A. Glucose
B. Galactose
C. Ribose
D. Sucrose
Paper II
EJE 4

5. 1. Outline the significance of the labeled parts of this diagram, showing the attraction between
three water molecules. [6]
w.
x.
y.
z.
δ-
δ+
2. Complete the table below: [6]
-saccharides examples Plant or animal? Function/ uses
animal
Mono-
plant
plant
Di-
animal
animal
Poly-
plant
3. Outline the relevance of the following properties of lipids. [3]
Energystorage
Thermalinsulation
Buoyancy
4. Label the structures of this single nucleotide. [3]
EJE 5

6. a.
b.
c.
5. Complete the table below to show the pairings of the bases in DNA: [4]
Purine Pyramidine
6. Transcribe and translate this DNA sequence. [4]
DNA T A C G G G C C C G T G A C A G C C A C T
mRNA
Amino
acid
7. Deduce the amino acids translated from these mRNA codons, using the table. [6]
AUG =
CAG =
UCA =
GAC =
AAA =
UGA/UAG =
8. Identify the stage of mitosis shown in the following diagrams by completing the table below. [8]
EJE 6

7. ¡Enjoy the Science!
EJE 7